LTE Macro-Femto Interference Optimization via UE Measurement
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Solution Overview
Problem
The introduction of femto base stations in LTE networks leads to increased interference with macro cells, causing deterioration in received quality and potentially creating 'blind zones' due to unnecessary shrinkage of macro cell coverage.
Innovation Solution
A system and method that enables identification of interference causes and appropriate optimization processing by instructing radio terminals to measure downlink signals from different types of base stations, allowing for targeted adjustments in radio network configurations to prevent unnecessary coverage changes and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If femto base stations are introduced to enhance network coverage and capacity, then network capacity and coverage in indoor areas are improved, but interference with macro cells increases causing deterioration in received quality and creation of blind zones
Solution Approach 1:
The patent segments interference measurement and analysis by dividing the network into macro cell base stations and femto cell base stations. The macro base station separately measures interference from femto cells and interference from other macro cells, enabling targeted optimization strategies for each interference source type.
Solution Approach 2:
The patent applies different optimization strategies based on the local quality and type of interference source. When femto cell interference is dominant, the system performs femto-macro interference optimization; when macro-macro interference is dominant, it performs coverage optimization. This localized approach allows appropriate handling of each interference scenario.
2Object-affected harmful factors
If macro cell coverage is shrunk to reduce interference, then interference levels are reduced, but blind zones are created and coverage is deteriorated
Solution Approach 1:
The patent implements a feedback mechanism where the macro base station continuously measures received quality from radio terminals and interference levels from different sources. Based on this feedback, the system determines whether to perform coverage optimization or interference optimization, creating a closed-loop control system that adapts to changing network conditions.
Solution Approach 2:
The patent changes optimization parameters based on interference source identification. When femto cell interference is detected as dominant, the system adjusts femto-macro interference optimization parameters; when macro-macro interference is dominant, it adjusts coverage optimization parameters. This dynamic parameter adjustment prevents unnecessary coverage shrinkage while maintaining interference control.
3Ease of operation
If received quality measurement is performed without distinguishing interference sources, then measurement simplicity is maintained, but accurate identification of interference causes and appropriate optimization processing cannot be achieved
Solution Approach 1:
The patent segments the interference measurement process by having the macro base station separately measure interference from femto cells and interference from other macro cells. This segmentation enables accurate identification of the dominant interference source while maintaining a systematic measurement approach that is integrated into the existing network infrastructure.
Data Source
AI summary
A system includes: first and second radio stations (eNB1,2) of a similar type and/or a third radio station (HeNB) of a different type, a radio terminal (UE) served by the eNB1; and an operation administration and maintenance server (OAM/SON server), wherein the eNB1 instructs the UE to measure interference from at least one of the second or third radio stations, the eNB1 and/or OAM/SON server receives a report of a measurement result by the UE, determines whether or not a change is to be made to the radio network configuration of the relevant radio station that is at least one of the first to third radio stations, and/or executes a change of the radio network configuration.